Electric welding apparatus



Jan. A12, 1943. A. B. soNNEBoRN ELECTRIC WELDING APPARATUS Filed Deo. 29, 1937 2 Sheets-Sheet l HJVEAITOR.` Eff/70k 5. o/me off/7 MMM A ORNEY.

Jan.'12, 1943.

A. B. SONNEBORN ELECTRIC WELDING APPARATUS Filed Dec 29, 1937 2 Sheets-Sheet 2 #W7/ WK ATTORNEY.

Patented Jan. 12, i943 OFFICE ELECTRIC WELDING APPARATUS 4Arthur B. Sonnehorn, Detroit, Mich.,` assigner to The Clark Controller Company, Cleveland, Ghia, a corporation of Ohio Application December 29. 1937, Serial No. 182,227 v (ci. 21e- 4) l2 Claims.

This invention relates to electric welding apparatus, and particularly to electric resistance welding apparatus of the type comprising a welding gun vor welding machine operated by i'luid pressure such as compressed air, to engage work to be welded between electrodes thereof, and an electric contactar which energizes an electric circuit to the electrodes for a tra: interval 'to cause a measured welding current impulse to through the among the obiectc or this mvention are:

To provide an improve1 electric contacter and an improved con' o provide f "ric contacto-r of pneumaticallv operated type;

provide a control for a welding current contactor which will cci-ordinate the functions thereof with. those of a welding gun or machine in an improved manner; f

To provide an improved means oi causing the electrodes of a welding gun or machine to remain engaged for a predetermined time interval after a welding current impulse has passed therethrough;

To provide improved means for timing the irequency at which successive operations of a welding current control contacter occur.

To provide an improved control for a welding current contactor in co-ordination with a welding gun or machine by which the contactar, only after the electrodes of the machine have engaged the work, will operate to close the welding current circuit to the electrodes for a timed interval, and

then interrupt it, and the electrodes will remain engaged for a time interval thereafter, and the contacter will then be conditioned for another operation. l

Other objects will be apparent to those skilled in the art to which my invention appertains. My invention is fully disclosed in the` following description taken in connection with the accompanying drawing, in which Fig. 1 is a view partly diagrammatic illustrating an embodiment of my invention and showing, in co-ordinated relation, a welding machine, a control gun therefor, and a welding current control contacter.

Fig. 2 is a longitudinal sectional view to enlarged scale of a part of the apparatus of Fig. 1.

Referring to the drawing I have shown generally at l a welding machine which may be of usual construction. The machine diagrammaticaliy illustrated comprises an upper head 2 and a lower head 3, the upper head having associated therewith a fluid pressure cylinder 6 in which a piston 5 reciprocates. an upper electrode 5 is connected to the piston and reciprocates therewith toward and from a. lower electrode l supported on the base 3 and when it reciprocates downwardly engages work i3 to be welded between the electrodes Ei and l under pressure.

The piston 5i is reciprocated downwardly by iluid pressure communicated to the upper side of the piston through a conduit and reciprocated upwardly by fluid pressure communicated to the lower side of the piston through a condtut the fluid pressure, which may be compressed air, 'be-- supplied in a manner to he described om a fluid pressure or compressed air source i i.

Current is supplied to the electrodes t and 'l from the secondary l2 of a transformer, the primary i3 of which is energized by wires ifl-i-il connected to movable switch arms i--l mounted on a rocking shaft it which, when it rocks in one direction, causes contacts illil on the arms iti-i5 to engage stationary contacts IS-il which are connected by wires i9 and 2t respectively to current supply mains ih and 22.

When the shaft i6 is oscillated in one direction itv engages the contacts il' and i@ to initiate the iow of current, and when oscillated in the other direction disengages the contacts to break the current, after a predetermined time interval to thereby time the duration of a welding current impulse.

To thus oscillate the shaft the following means is provided. The shaft I6 is osciliatably supported in a bearing 23 at one end and at the other end in abearing 24 on a. bracket 25 mounted on a panel 25. An arm 21 is secured to the shaft and has on the upper end portion thereof a finger 21 carrying a roller 28, the finger being normally rocked around a pivot 29 against a stop 30 by a spring 3|l the arrangement being such that the finger |21 may be rocked counter-clockwise.

Upon the bracket 25 is supported a iiuid pressure cylinder 32 Within which reciprocates a. piston 33 mounted on a piston rod 34. At the upper end of the piston rod 34 is connected a plunger 35. The piston' rod reciprocates in a bore 36 which guides the lower end of the plunger and the upper end of the plunger reciprocates in a bore 31 on the bracket 25.

A cam 38 is secured to the plunger, and when the plunger is in its normal downward position an inclined cam face 39 on the cam is disposed adjacent to and under the roller 28. When the plunger 35 is reciprocated upwardly upon the application of fluid pressure to the cylinder 32 on the under side of the piston 33, the cam face 39 in the direction to engage the contacts |1|8;

and after the cam has passed beyond the roller,

' a spring 40 abutting at one end upon the arm 21 and at the other end upon the brackets oscil- A lates the arm 21 inthe other direction to disengagethe contacts. Upon the downward stroke of the plunger when pressure is removed from the cylinder 32, the cam 38 engages the roller 20 and rocks the finger |21 so that the roller is moved out of the path of the descending cam without moving the arm 21 If movement of the plunger 35 is relatively slow, the roller 28 will remain in engagement with the cam face 39 and the length of the current impulse will be determined by the rate of movement of the plunger 35. If the movement of the plunger 35 however is very rapid., the roller 28 and the arm 21 will be kicked away from the cam face 39 when theroller is engaged thereby and the length of the current impulse-may be determined by the strength of the spring 40 and the inertia of the arm 21 which may be supplemented by a weight 4I on the arm. The counter-clockwise position of the arm 21 may be positionally determined by a stud 42 on the arm engaging the bracket 25.

The plunger 35 is normally held in its downward position and is returned thereto by a spring abutting at its lower end upon the upper end of the plunger, and at its. upper end abutting on a bracket 48 forming part of the bracket 25 or secured thereto. f l

The arrangement above described for engaging the contacts |l1|8 for a timed period to initiate, time, and interrupt the current, constitutes no essential part of the present invention excepting so far as it is co-ordinated with other parts and functions to be .described such a switch constituting the lsubject matter of 'the co-pending application of Edward G. Beiderman, for improvements in 'Iime controlled electric switches, filed June 13, 1936, Serial Number 34,981, and attention is directed thereto, for a more complete showing and description of the structure which is herein shown diagrammatically. l

Fluid pressure, such as compressed air, from the source |I is supplied to the cylinder 32 by a conduit 43 through a valve housing 44. Within the valve housing is a fluid pressure supply duct 41 and a uid pressure exhaust duct 48 for the cylinder 32, as illustrated, and also within the valve housing 44 may be provided a valve which throttles the uid pressureto the cylinder 32 as an additional means to control the` velocity `of movement of the plunger 35 to time the current at the contacts I1 and4 I8; and also valve means to direct iluid pressure to the cylinder 32 by the duct 41 or to exhaust it therefrom by the duct 48, and while these and other parts and their functions constitute no essential part of the present invention, one illustrative construction thereof is illustrated in Fig. 2 of the drawing and will now be described.

In this lconnection it may be added that subject matter illustrated and described herein but Anot claimed is claimed in said co-pending application, Serial Number 84,981 and in the co-pending application of Charles H. Rippel, Serial Number 120,862, filed January 13, 1937, for improvements in Pressure controls for pnuematically operated switches.

'I'he valve housing 44 referred to, and which is valve as illustrated being normally held against the end of a duct |06 to close the same, by a spring |01, the upper end of which engages the valve vand the lower end of which engages an adjusting screw |08. Preferably the valve |04 is of the trunk piston type and the upper portion of the spring yis enclosed within the valve.

An annular chamber |09 surrounds the valve and communicates with the bore |055 The valve has an annular groove ||0 therein axially spaced from the chamber |09.

The annular chamber |09 communicates with 'a bore which communicates with-the uid pressure supply duct 41, the said communication being controlled by a needle valve I|2 having a lower threaded portion ||3, threaded into the housing, whereby the ow of fluid pressure to the duct 41 may be adjustably regulated. The conduit 43, threaded into the housing 44 at ||4 communicates with a duct ||5 in the housing which in turn communicates with the duct |06 referred to.

A duct IIS communicates at an upper portion with th'elexhaust duct 48 and at a lower portion connnunlcates with the annular groove ||0, of

.the valve, when in its normal position, by a duct ||1. The lower end of the duct 48 is normally closed by a check ball valve II8. A spring IIS` holds the valve ||8 seated uponl the end of the duct 48, and the tension of the spring may be adjusted by a screw L20. The upper end of the screw |20 furthermore is disposed opposite the end of the duct ||1, and adjustment of the screw controls the eiective size of the duct ||1.

A duct |2| communicates between the duct ||5 and the valve groove ||0, in its normal position.

Pressure in the conduit 43 communicatedl through the ducts ||5 and |06, when said pressure is at a valve predetermined as suicient by the adjustment of the spring |01, acting upon the upper end of the valve |04, moves it downwardly against the spring tension until the upper end of the valve comes into alignment with the annular chamber |09. Thereupon pressure from the duct |06 flows into the chamber '|09 and passing the valve |04 flows through the ducts and 41 to the cylinder 32 to operate the piston 33 for the purposes described, the upward movement of the pieton being at a rate determined by the adjustment of the needle throttle valve Il2.

When pressure in the conduit 43 is removed, and the piston 33 is moved downwardly, as described, thereleaUse of pressure in the duct |08 permits the spring` |01 to again raise and seat the valve |04 in its normal position. Downward movement of the piston 33 exhausts the pressure from the cylinder 32 through the exhaust duct 48 moving aside the valve I8, and the pressure ows into the duct IIB and thence through the duct ||1 to the annular groove I|0, through the duct |2| to the duct ||5 and thence out by conduit 43.

This exhausts the cylinder 32 and the rate of the exhaust may `be controlled by adjustment of the screw |20 to more or less open the duct When, as described above, pressure is admitted from duct |08 to the annular chamber |09 and communicated by a duct |22 from the chamber the gun by a grip B2,

09 to the duct H6 and holds the ball valve H8 firmly against its seat, holding the duct 48 closed and preventing leakage of pressure out of the chamber 32.

Mounted upon the bracket 25 isa valve hous.-

ing 49 in which reciprocates a,piston valve 50 vtion is spaced from the stop 53 but when the plunger 35 moves upwardly the arm 54 engages the stop 53 and lifts the valve 59 to an upper position. The valve 56 is normally held down by a spring 55 the bracket 25. A

The purposes of the valve U and other parts within the housing i9 will presently be described. Indicated generally at 5S is a fluid pressure operated valve device, the parts for which are mounted on a panel 51. It comprises a bracket 5t provided with a uid pressure cylinder 5t supplied with iluid pressure by e. conduct-Sti from the source il in a manner to be described, and having a piston @i reciprocable therein, the piston rod 62 of which hase. stop @3 thereon normally supporting the piston in a downward position. The piston is held downwardly by a spring Bil abutting upon the bracket S and upon a collar on the upper end portion of the piston rod, which is enlarged into the forni of a valve plunger rrhe plunger has a duct longitudinali; 'tLeretnrough which in the lower part thereof errand" aterally es at is conduit conneod d .roe ii of uid press r "l nected to a verv ving a planar sull ure against a planar oy a reir he described. liilustrated generally a" 'i' hv which operations oi" app d to eect weide the machine a ts of 'the gun as weli as parte of pressure operated valve device and parts within the valve housing not described above, will new be described in connection with a inode operation of the apparatus which follows. With the parts in the' normal position shown, fluid under pressure from the source il conducted oy a conduit to a duct VI in the valve housing il@ .is cut o at the inner: end or the duet by the valve The fluidvpressure is also communioated from the source il to the conduit QQ and thence by the duct @l in the piston plunger and may iiow upwardly therethrough into the valve lil, through a duct 'i8 therein, and through a duct l@ with which it is normally aligned, to a ,conduit du connected to the gun `Flow through the conduit d@ is cut oil' at the gun by a valve di.` Thus no fluid can iiow irorn the source. To perform a weld on the work at the machine i, the gun operator, who holds pulls a trigger 83 which abutting upon the valve and upon' reciprocates rearwardly a-plunger 84 connected to the valve 8i which opens the valve 3! allowing the iiuid under pressure to flow from the conduit around the valve 8i into a duct 35 and out at a duct 86, to the conduit 9, the movement of the plunger 84 closing the inner end of the duct 85 by a valve 81.

Fluid pressure in the ducts is communicated to a conduit 83 bywhich the huid ows into a cylinder B ln the gun and acting upon a piston in the cylinder moves a piston rod 9i inwardly, the inner end of which engages the trigger 83 and holds it in the operated position so that it will remain operated even if the operator removes his finger from it.

Fluid pressure in the conduit 9, also communicated to the cylinder il, moves the piston 5 downwardly to engage the electrodes 6 and i with the worlr.

The uid pressure in the conduit 9 is communicated to a conduit connected therewith or with the cylinder il, above the piston and thence by ducts and @lll is communicated to the conduit d3 and thence to the switch cylinder but during the movement of the piston 5, tins pressure is less than source pressure and inscient to overcome the spring G5, which .holds the piston downwardiy to `the cylinder so that no further action taires place.

ifi/"hen, however, the piston i has reached the bottoni of :its stroke and engages the work with pressure, the pressure ln the cylinder above the piston, and 'therefore in the conduits, and F13, rises and reaches the valve at which it is able to move the valve ldd and admit pressure to the cylieder raise the plunger lt e noted du movement o exhausts at this t1' were@ by its lower n l predetermines a time interval during which tn electrodes remain engaged with the work after the current is cut oi, such a holding period sometimes referred to as cold hold contro After e. determined upward movement of the valve the duct le is aligned with the duct S5, the duct itl is aligned with an exhaust duct SS, and the duct @il is uncovered by the lower end of the valve. As o. result of these changes, which occur after a, timeinterval, the cylinder 4 of the welding machine 2 exhausts through the conduit and the conduit S2 and ducts 93 and Si; and Iluid pressure is supplied to the cylinder 4 belowl the piston 5 from the source n, by conduit ss,-

'90 and trigger 83 to their normal position for another operation.

When the plunger 35 returned downwardly as described, the spring 5,5 restored the valvel 50 downwardly establishing an exhaust for the valve cylinder 59 by way of the conduit 60, duct 98 and around the valve neck 96 and out at an exhaust i112, the air flowing past a throttle valve m3 whereby the rate of return of the valve l0 is delayed ior a time interval. Inasmuch as another operation of the apparatus cannot be performed until the valve l0 has returned to its lower posi# tion, this time delay predetermines the frequency at which successive operations may be performed. It will be noted that after the valve 3l has once been operated by the trigger 33, it is held operated independently of the trigger at least until after the contactor contacts li-l have closed and again opened so that the contactor operatingcycle when once-started cannot be interrupted by a succeeding premature operation of the trigger.

To resume in brief, when the gun l5 is operated, it is automatically held operated and uid.

pressure is supplied to the welding machine l which engages the electrodes with the work; and when the pressure in the cylinder 4 thereof has risen to a sufficiently high value, suicient to move the valve 1104, the switch contacts l1 and.

I8 are engaged and then disengaged sending a timed current impulse through the electrodes and the Work, and the valve 50 is raised. 'I'his sets into action the valve device 56 which operates the valve l0 after a suitable time interval during which the electrodes remain engaged with the work, althoughthe current is cut off. When the valve device 56 has operated, it restores the gun 15, and disengages the electrodes from the work V restoring the machine l, and restores the plunger 35 downwardly, resetting the valve 50, and then restores itself, it being completely restored after another time interval. The time interval during the operation of the device 56 determines the time of the cold hold and the time interval during the restoring of the device 56 determines the possible frequency of successive operations.

Both time periods may be adjusted respectively by the valve screws S1 and |03 as described, and independently of each other; and by no adjustment can the valve device 56 be made to operate ahead of the contactar.

The duration of the welding current may be adjustably changed by the screw l li: which throttles the supply of pressure to the cylinder 32, and the rate of return of the plunger 35 may be controlled by the screw |20 which throttles the exhaust from the cylinder 32.

My invention is not limited to the exact details of construction illustrated and described, since it is obvious that changes and modifications may be made within the spirit of my" invention without sacricing its advantages and my invention is comprehensive .of all such modications and changes which come Within-the scope of the ap-y pended claims.

, Iclaim:

1. In an electric welding system an electric welding machine having electrodes and an electrode energizing electric circuit and comprising electrode operating means to pressure-engage the e1ectrodes`,with work to be welded, an electric contactor, movable contactor operating means to close the circuit and maintain it closed for a predeterminecitime interval and then open it to effect an electric weld at the electrodes, timing means controlling the electrode operating means to maintain pressure engagement of the electrodes with the work. for a predetermined time interval after opening of the circuit, actuating means for the timing means, and control means operated by movement of the contacter operating means to control actuation of the timing means.

2. In an electric welding system an electric welding machine having electrodes and an electrode energizing electric circuit and comprising electrode operating means to pressure-engage the electrodes with work to be welded, an electric contactor, contacter operating means to close the circuit and maintain it closed fora predetermined time interval andv then open it to eiiect an electric weld at the'electrodes, timing means controlling the electrode operating means to main- -tain pressure engagement of the electrodes with the work for a predetermined time interval after opening of the circuit, said timing means also controlling the contacter operatingl means to prevent a successive closure of the circuit thereby until after a second predetermined time interval, actuating means for the timing means, and control means operated by the contacter operating means to control actuation-of the timingmeans. 3. In an electric welding system, a source lof uid pressure, a welding machine having electrodes and an electrode energizing electric circuit and comprising uid pressure means actuated by uid pressure from the source to pressure-engage the electrodes with work to be welded, an electric contactor, uid pressure actuated means to operate the contactor to close the electric circuit and maintain it closed for a predetermined time interval and then open it, a fluid pressure operated timing means, a valve operated by the contactor operating means to effect actuation of the timing means by -pressure from the source, and said timing means controlling the supply of uid pressure from the source to the welding machine to maintain the electrodes pressure engaged with the work for a predetermined time interval after opening of the circuit. v`

` 4. In an electric welding system, a source of fluid pressure, a welding machine having electrodes and an electrode energizing electric circuit and comprising fluid pressure means actuated by fluid pressure from the source t0 pressure-engage the electrodes with work to be welded, an electric contactor, fluid pressureactuated means to operate the contacter to close the electric circuit and maintain it closed for a predetermined time interval and then open it, a fluid pressure operated timing mea/ns, a valve operated by the contacter operating means to eiect actuation of the timing means by pressure from the source, said timing means controlling the Asupply of fluid pressure from the source to the welding machine to maintain the electrodes pressure engaged with the work for a predetermined time interval after opening of the circuit andsaid timing means controlling Supply of uid pressure to the contactor operating means to prevent supply of, uid pressure thereto from the source until after determined time interval. 4'

5. In an electric welding system, a sourcefof fluid pressure, a weldingmachine-comprising electrodes and an electrode energizingl electric circuit and fluid pressure operated means to eiect pressure engagement of the electrodes with the work a second pre-l to be Welded, a normally restored contactor, iluid pressure operated means to effectz operation of the contactor to close thecircuit and maintain it i closed for a time interval and then open it, a

means to retard restoring thereof, the valve device controlling supply of fluid pressure to the welding machine to maintain theV electrodes pressure engaged with the Work for a time interval after opening of the circuit and also controlling supply o'f fluid pressure to the contactor operating means to prevent a successivev operation thereof until after a second predetermined time interval. 6. In an electric welding system on electric welding machine having electrodes and en electrode energizing electric circuit and comprising electrode operating means to pressure-engage the electrodes with work to be welded, an electric contactor, contactor operating means ,to close the circuit and maintain it closed for a predetermined time interval and then open it to effect an electric weld at the electrodes, timing means controlling the contactor operating means to prevent a successive closure of the circuit thereby until after a second predetermined time interval, actuating means for the timing means, and control means operated by the contactor operating means to control actuation of the timing means.

7. In an electric welding system, a source of uid pressureL a welding machine having electrodes and an electrode energizing electric circuit and comprising 'duid pressure means actuated by fluid pressure from the source to pressure-engage the electrodes with work to be welded, an electric contactor, uid pressure operating means to operate the contactor to close the electric circuit and lmaintain it closed for a predetermined time inter- Y val and then open it, fluid pressure operated tming means, a valve operated by the contactor operating means to effect actuation of the timing means by pressure from the source, and said timing means controlling the supply of iiuid pressure from the source to the welding machine to maintain the electrodes pressure engaged with the work for a predetermined time interval after opening of the circuit.

8. In an electric welding system, a source of fluid pressure, a welding machine having electrodes and an electrode energizing electric circuit and comprising fluid pressure means actuated by means. controlling the supply of viluid pressure effecting actuation of the electrode operating from the source to the welding machine to maintain the electrodes pressureeng'aged with the.

work for a predeterminedtime interval after opening of the circuit and said timing means con-- trolling the contactor operating means to prevent a successive closure of the circuit thereby until after. a second predetermined time interval.

9. In an electric welding system, a source of fluid pressure, a welding machine having electrodes and an electrode energizing electric circuitA and comprising iluid pressure means actuated by iiuid pressure from the source to pressure-engage the electrodes with the Work to be welded, an electriccontactor, iiuid pressure actuated means `to operate the contactor to close the electric circuit and to maintain it closed for a predetermined time interval and then open it, fluid pressure operated timing means, a valve operated by the contactor operating means to eiect actuation of the timing means by pressure from the source, said timing means controlling supply of fluid pressure to the contactor operating means to prevent supply of pressure thereto from the source until after a predetermined time interval.

10.-\In anelectric welding system, a source of iluid pressure, a welding machine having electrodes and an electrode energizing electric circuit and comprising iluid pressure means actuated by fluid pressure from the source to pressure-engage the electrodes with the work to be welded, an electric contactor, contactor operating means to operate the contactor to close the electric circuit and maintain it closedy for a predetermined time interval and then open it, fluid pressure operated timing means, a valve operated by the contactor operating means to effect actuation of the timing means by pressure from the source, said timing means controlling the contactor operating means to prevent a successive closure of thescircuit until after a predetermined time interval.

11. In an electric welding system, an electric welding machine having electrodes, and an electrode energizing electric circuit and comprising electrode operating means to pressure-engage the electrodes with work to be welded, an electric contactor operating means to close the circuit and to maintain it closed for a predetermined time interval and then open it to eiect an electric weld at the electrodes, manually operable means for means and contactor operating means, timing means actuated by the contactor operating means and holding means to maintain the manually operable `means operated for a time period of the timing means.

l2. In an electric welding system, a source of iluid pressure, a welding machine having electrodes and an electrode energizing electric circuit and maintain it closed for a predetermined time I interval and then open it, a fluid pressure timing means, actuated by operation of the contactor manually operable means for effecting com-` munication of fluid pressure to the electrode fluid pressure actuated means and to the contactor uid pressure actuating means, and iluid pressure operable holding means for maintaining the manually operable means operated for "a time period of the iluid pressure timing means.

- ARTHUR B. SONNEBORN. 

